All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.
Undoubtedly, imitating the disbelievers is condemned in Sharee‘ah. It is narrated that the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, said: “He is not from us who imitates other than us (Muslims). Imitate neither the Jews nor the Christians…” [At-Tirmithi] According to another wording, “Whoever imitates a people belongs to them.” [Ahmad]
But the criterion of forbidden imitation, as mentioned by scholars, is to do something characteristic of the imitated, which none shares with them. It is well-known that transporting the deceased to the grave to be buried in a hearse or any other vehicle specified for carrying the deceased is common among the Muslims and not unique to the disbelievers. Hence, it is not an imitation of them.
Allaah Knows best.